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Abstract:

A projection-type display device according to an embodiment of the
invention modulates light emitted from a solid-state light source array
and projects the modulated light on a screen. The projection-type display
device includes a power source device that generates power used for
driving the solid-state light source array using power supplied from a
power source, an instant interruption detecting circuit that detects an
instant interruption of the power source, and a control device that, in a
case where the instant interruption of the power source is detected by
the instant interruption detecting circuit, performs control of
extinguishing the solid-state light source array during at least a part
of an instant interruption period until recovery after the detection of
the instant interruption of the power source.

Claims:

1. A projection-type display device comprising: a solid-state light
source; an optical modulation device that modulates light emitted from
the solid-state light source; a projection optical system that projects
the light modulated by the optical modulation device on a screen; a power
source device that generates power used for driving the solid-state light
source using power supplied from a power source; an instant interruption
detecting device that detects an instant interruption of the power
source; and a control device that, in a case where the instant
interruption of the power source is detected by the instant interruption
detecting device, performs control of extinguishing the solid-state light
source during at least a part of an instant interruption period until
recovery after the detection of the instant interruption of the power
source.

2. The projection-type display device according to claim 1, wherein the
control device performs control of extinguishing the solid-state light
source over an entirety of the instant interruption period.

3. The projection-type display device according to claim 1, wherein the
control device performs control of intermittently extinguishing the
solid-state light source by intermittently stopping the power supplied
from the power source device to the solid-state light source through
pulse-width modulation.

4. The projection-type display device according to claim 1, wherein the
solid-state light source includes a plurality of solid-state light source
elements, and wherein the control device performs control of
extinguishing at least one of the solid-state light source elements
during at least a part of the instant interruption period.

5. The projection-type display device according to claim 4, wherein the
control device performs control of extinguishing a part of the
solid-state light source elements and intermittently extinguishing a
remaining part of the solid-state light source elements over an entirety
of the instant interruption period.

6. The projection-type display device according to claim 4, wherein the
control device performs control of sequentially changing the solid-state
light source element to be extinguished out of the solid-state light
source elements.

7. The projection-type display device according to claim 6, wherein the
control device changes the solid-state light source elements to be
extinguished in units of the solid-state light source elements
corresponding to a number set in advance.

8. The projection-type display device according to claim 1, wherein the
control device performs control of decreasing a current supplied to the
solid-state light source during a period, in which the solid-state light
source is lighted, in the instant interruption period.

9. A method of controlling a projection-type display device that includes
a solid-state light source, an optical modulation device that modulates
light emitted from the solid-state light source, and a projection optical
system that projects the light modulated by the optical modulation device
on a screen, the method comprising: detecting an instant interruption of
a power source that is used for generating power used for driving the
solid-state light source; and performing control of extinguishing the
solid-state light source during at least apart of an instant interruption
period until recovery after the detection of the instant interruption of
the power source in a case where the instant interruption of the power
source is detected in the detecting of an instant interruption of the
power source.

Description:

BACKGROUND

[0001] 1. Technical Field

[0002] The present invention relates to a projection-type display device
such as a projector and a method of controlling thereof.

[0003] 2. Related Art

[0004] As is widely known, a projection-type display device such as a
projector is a device that includes a light source, an optical modulation
device, and a projection lens and displays an image on a screen by
modulating light emitted from the light source by using the optical
modulation device and projecting the modulated light onto the screen by
using the projection lens. Generally, projectors include a lamp such as a
halogen lamp, a metal halide lamp, or a high-pressure mercury lamp as the
light source. However, recently, projection-type display devices
including solid-state light sources such as an LD (Laser Diode) and an
LED (Light Emitting Diode) have been actively developed.

[0005] Here, the above-described various lamps used as light sources of
the projectors have characteristics that the lamps are extinguished at a
time when an applied voltage is lower than a specific voltage and it
takes a long time (for example, several minutes or more time) for the
lamps to be relighted. Accordingly, in a general projector including such
a lamp, a circuit is arranged which is used for maintaining the lighting
state of the lamp for an interval (for example, about one second) of some
degree even in a case where an instant interruption (instant voltage
drop) of the power source occurs.

[0006] In JP-A-2004-303507, a device is disclosed which decreases a
current output from a converter circuit by changing PWM (Pulse Width
Modulation) control for the converter circuit so as to avoid rapid
consumption of interlay-stored energy in a case where an input voltage is
lowered to be equal to or lower than a predetermined value, thereby
maintaining discharge of a lamp. In addition, in JP-A-2002-367791, a
device is disclosed which performs a countermeasure of an instant
interruption by decreasing the power supplied from a capacitor to a
discharge lamp based on a detection result of an instant interruption
detecting unit that detects an instant interruption of the power source.

[0007] However, a solid-state light source, differently from the
above-described various lamps, has characteristics that it can be
instantly relighted by supplying a predetermined current used for
lighting the solid-state light source even when the applied voltage is
lowered to zero [V]. Accordingly, in a projector including a solid-state
light source as a light source, unlike JP-A-2004-303507 and
JP-A-2002-367791, it may be thought that control of continuously
supplying minimum power necessary for lighting the lamp to the lamp in a
case where an instant interruption occurs is unnecessary, and a circuit
used for maintaining the lighting state of the lamp is unnecessary.

[0008] However, in a case where the circuit used for maintaining the
lighting state is omitted in the projector including the solid-state
light source, the display of an image on a screen is stopped when an
instant interruption occurs, and there is a concern that a user may
erroneously determine that the projector is out of order. In addition, in
order to redisplay the image that has been stopped due to the instant
interruption on the screen, the user needs to input power to the
projector again, and accordingly, the user is compelled to perform an
inconvenient operation. Considering such problems, also in the projector
including a solid-state light source, the circuit used for maintaining
the lighting state in a case where an instant interruption occurs needs
to be included.

[0009] Here, the circuits disclosed in JP-A-2004-303507 and
JP-A-2002-367791 described above need to continuously supply minimum
power necessary for lighting the lamp to the lamp when an instant
interruption occurs. Accordingly, there are problems in that the
efficiency is low, and the period during which lighting can be maintained
is limited. In addition, since the power supplied to the lamp is not
allowed to be equal to or lower than the minimum power, there is a
problem in that a countermeasure in which the lighting period is
lengthened by performing precise control cannot be performed.

SUMMARY

[0010] An advantage of some aspects of the invention is that it provides a
projection-type display device and a method of controlling thereof that
are capable of lengthening a period during which the solid-state light
source can be lighted in a case where an instant interruption of the
power source occurs.

[0011] An aspect of the invention is directed to a projection-type display
device including: a solid-state light source; an optical modulation
device that modulates light emitted from the solid-state light source; a
projection optical system that projects the light modulated by the
optical modulation device on a screen; a power source device that
generates power used for driving the solid-state light source using power
supplied from a power source; an instant interruption detecting device
that detects an instant interruption of the power source; and a control
device that, in a case where the instant interruption of the power source
is detected by the instant interruption detecting device, performs
control of extinguishing the solid-state light source during at least a
part of an instant interruption period until recovery after the detection
of the instant interruption of the power source.

[0012] According to the above-described projection-type display device,
when an instant interruption of the power source is detected by the
instant interruption detecting device, the control device performs
control of extinguishing the solid-state light source during at least a
part of an instant interruption period until recovery after the detection
of the instant interruption of the power source. Accordingly, the power
consumption of the solid-state light source is reduced, and a period
during which the solid-state light source can be lighted can be
lengthened, compared to a general case.

[0013] The above-described projection-type display device may be
configured such that the control device performs control of extinguishing
the solid-state light source over an entirety of the instant interruption
period.

[0014] In such a case, when an instant interruption of the power source
occurs, the solid-state light source is extinguished over the entirety of
the instant interruption period, whereby the power consumption of the
solid-state light source can be configured to be almost zero. Here, by
performing control of lighting the solid-state light source at an
arbitrary timing, the solid-state light source can be instantly relighted
by the accumulated power.

[0015] The above-described projection-type display device may be
configured such that the control device performs control of
intermittently extinguishing the solid-state light source by
intermittently stopping the power supplied from the power source device
to the solid-state light source through pulse-width modulation.

[0016] In such a case, when an instant interruption of the power source
occurs, the power supplied from the power source device to the
solid-state light source is intermittently stopped through pulse-width
modulation so as to intermittently extinguish the solid-state light
source. Accordingly, the average light intensity of light emitted from
the solid-state light source decreases. Therefore, the power consumption
of the solid-state power source is reduced, and accordingly, the period
during which the solid-state light source can be lighted can be
lengthened, compared to a general case.

[0017] The above-described projection-type display device may be
configured such that the solid-state light source includes a plurality of
solid-state light source elements, and the control device performs
control of extinguishing at least one of the solid-state light source
elements during at least a part of the instant interruption period.

[0018] Here, the control device may perform control of extinguishing a
part of the solid-state light source elements and intermittently
extinguishing a remaining part of the solid-state light source elements
over an entirety of the instant interruption period.

[0019] Alternatively, the control device may perform control of
sequentially changing the solid-state light source element to be
extinguished out of the solid-state light source elements.

[0020] At this time, the control device may change the solid-state light
source elements to be extinguished in units of the solid-state light
source elements corresponding to a number set in advance.

[0021] Furthermore, the control device may perform control of decreasing a
current supplied to the solid-state light source during a period, in
which the solid-state light source is lighted, in the instant
interruption period.

[0022] In such cases, the plurality of solid-state light source elements
disposed in the solid-state light source can be controlled to be lighted
and extinguished in various manners. Accordingly, the power consumption
of the solid-state light source can be precisely controlled as is needed.

[0023] Another aspect of the invention is directed to a method of
controlling a projection-type display device that includes a solid-state
light source, an optical modulation device that modulates light emitted
from the solid-state light source, and a projection optical system that
projects the light modulated by the optical modulation device on a
screen. The method includes: detecting an instant interruption of a power
source that is used for generating power used for driving the solid-state
light source; and performing control of extinguishing the solid-state
light source during at least a part of an instant interruption period
until recovery after the detection of the instant interruption of the
power source in a case where the instant interruption of the power source
is detected in the detecting of an instant interruption of the power
source.

[0024] According to the above-described method, when an instant
interruption of the power source is detected in the detecting of an
instant interruption of the power source, control of extinguishing the
solid-state light source during at least apart of an instant interruption
period until recovery after the detection of the instant interruption of
the power source is performed in the performing of control of
extinguishing the solid-state light source. Accordingly, the power
consumption of the solid-state light source is reduced, and a period
during which the solid-state light source can be lighted can be
lengthened, compared to a general case.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will be described with reference to the accompanying
drawings, wherein like numbers reference like elements.

[0026]FIG. 1 is a block diagram showing the entire configuration of a
projector as a projection-type display device according to an embodiment
of the invention.

[0027]FIG. 2 is a diagram schematically showing a solid-state light
source array included in a projector.

[0028]FIG. 3 is a block diagram showing the configuration of a main part
of a driving circuit of a light source device included in a projector.

[0029]FIG. 4 is a flowchart showing the overview of an operation
performed by a projector when an instant interruption occurs.

[0030]FIG. 5 is a diagram showing an example of a change in the optical
output of a light source device included in a projector when an instant
interruption occurs.

[0031]FIG. 6 is a diagram showing another example of a change in the
optical output of a light source device included in a projector when an
instant interruption occurs.

[0032]FIG. 7 is a diagram showing yet another example of a change in the
optical output of a light source device included in a projector when an
instant interruption occurs.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0033] Hereinafter, a projection-type display device according to an
embodiment of the invention will be described with reference to the
accompanying drawings. The embodiment described below represents some
aspects of the invention, is not for the purpose of limiting the scope of
the invention, and may be arbitrarily changed within the scope of the
technical concept of the invention. Hereinafter, a projector as an
example of the projection-type display device will be described.

[0034]FIG. 1 is a block diagram showing the entire configuration of a
projector as a projection-type display device according to an embodiment
of the invention. As shown in FIG. 1, the projector 1 includes an
illumination device 10, a color separating light guiding optical system
20, liquid crystal optical modulation devices 30R, 30G, and 30B (optical
modulation devices), a cross dichroic prism 40, and a projection optical
system 50. The projector 1 displays an image on a screen SCR by
projecting image light according to an image signal input from the
outside toward the screen SCR.

[0035] The illumination device 10 includes a light source device LS, a
first lens array 16, a second lens array 17, a polarization converting
device 18, and a superposing lens 19 and emits white light that includes
red light, green light, and blue light. The light source device LS
includes a solid-state light source array 11 (solid-state light source),
a collimator lens array 12, a light collecting optical system 13, a
fluorescence generating unit 14, and a collimator optical system 15 and
emits white light as a whole.

[0036]FIG. 2 is a diagram schematically showing a solid-state light
source array included in a projector. As shown in FIG. 2, the solid-state
light source array 11 includes a substrate SB and a plurality of
solid-state light source elements 11a and is driven so as to emit blue
light by a driving circuit 60 (see FIG. 3). The substrate SB is a
plate-shaped member having an approximately rectangular shape on which
the solid-state light source elements 11a are mounted. This substrate SB
has functions of relaying the power supply to the solid-state light
source elements 11a and discharging heat generated from the solid-state
light source elements 11a.

[0037] The solid-state light source elements 11a are semiconductor laser
devices that emit blue light (peak emission intensity: about 460 nm) and
are arranged on the substrate SB in a matrix pattern. In the example
shown in FIG. 2, 56 solid-state light source elements 11a are arranged on
the substrate SB in a matrix pattern of 7 rows and 8 columns, and the
solid-state light source elements 11a arranged in the same row are
connected in series. In other words, eight solid-state light source
elements 11a arranged in a row to which a sign C1 is assigned are
connected in series, and eight solid-state light source elements 11a
arranged in a row to which a sign C2 is assigned are connected in series.
The solid-state light source elements 11a arranged in rows to which signs
C3 to C8 are assigned are similarly connected respectively.

[0038] The solid-state light source array 11 shown in FIG. 2 can control
lighting and extinguishing of the 56 solid-state light source elements
11a arranged on the substrate SB in units of eight solid-state light
source elements 11a (eight solid-state light sources elements 11a
connected in series) arranged in each of the rows C1 to C8. It is
apparent that, by changing a current flowing through the solid-state
light source elements 11a arranged in each of the rows C1 to C8, the
intensity of emitted blue light can be continuously changed. Even when
the solid-state light source elements 11a are extinguished once, by
supplying a predetermined current thereto, the solid-state light source
element 11a can be instantly relighted. In this embodiment, an example is
described in which 56 solid-state light source elements 11a are arranged
in a matrix pattern of 7 rows and 8 columns, and the solid-state light
source elements 11a arranged in the same row are connected in series.
However, the total number, the method of arrangement, and the method of
connection of the solid-state light source elements 11a are arbitrary.

[0039] The collimator lens array 12 includes a plurality of collimator
lenses corresponding to the plurality of solid-state light source
elements 11a disposed in the solid-state light source array 11 and
approximately parallelizes the blue light emitted from each solid-state
light source element 11a. To be more specific, the collimator lens array
12 is formed by arranging the collimator lenses that are 56 plane convex
lenses in a matrix pattern of 7 rows and 8 columns. This collimator lens
array 12 is arranged such that the convex face of the collimator lens
faces the solid-state light source array 11, and the collimator lenses
are in correspondence with the solid-state light source elements 11a.

[0040] The light collecting optical system 13 includes a first lens 13a
and a second lens 13b and collects the blue light that is approximately
parallelized by the collimator lens array 12 at a position near the
fluorescence generating unit 14. The first lens 13a and the second lens
13b are configured by biconvex lenses. In addition, lenses other than the
biconvex lenses can be used as the first lens 13a and the second lens 13b
as long as they can collect the blue light emitted from the collimator
lens array 12 to a position near the fluorescence generating unit 14.
Here, the number of lenses configuring the light collecting optical
system 13 may be one, or three or more.

[0041] The fluorescence generating unit 14 is disposed near a light
collecting position of the light collecting optical system 13 and
includes a fluorescent layer (not shown in the figure) that generates
fluorescence including red light and green light from a part of the blue
light collected by the light collecting optical system 13 and a
transparent member (not shown in the figure) that supports the
fluorescent layer. To be more specific, the fluorescence generating unit
14 is disposed at a position at which the blue light collected by the
light collecting optical system 13 is incident to the fluorescent layer
in a defocused state. The fluorescence generating unit 14 emits light
that includes blue light passing through the fluorescent layer without
being related to generation of the fluorescence together with the
fluorescence and is white light as a whole.

[0042] The above-described fluorescent layer is formed from a layer that
contains (Y,Gd)3(Al,Ga)5O12:Ce as a YAG-based fluorescent
body. The fluorescent layer may be formed from a layer that contains a
YAG-based fluorescent body other than
(Y,Gd)3(Al,Ga)5O12:Ce, a layer that contains
silicate-based fluorescent body, or a layer that contains a TAG-based
fluorescent body. Furthermore, the fluorescent layer may be formed from a
layer that contains a mixture of a fluorescent body (for example, a
CaAlSiN3 red fluorescent body) converting main excitation light into
red light and a fluorescent body (for example, a β sialon green
fluorescent body) converting the main excitation light into green light.

[0043] The fluorescent layer converts a part of the blue light collected
by the light collecting optical system 13 into fluorescence including red
light (peak of the emission intensity: about 610 nm) and green light
(peak of the emission intensity: about 550 nm) and emits the converted
fluorescence. A part of the blue light passing through the fluorescent
layer without being related to generation of fluorescence is emitted
together with the fluorescence. At this time, since the blue light is
scattered or reflected within the fluorescent layer, the blue light is
emitted from the fluorescent layer as light having the almost same
distribution (a so-called Lambertian distribution) characteristics as the
fluorescence. Here, the transparent member that supports the fluorescent
layer, for example, may be formed of quartz glass or optical glass, and a
layer (so-called dichroic coat) that transmits excitation light and
reflects fluorescence may be formed on the light collecting optical
system 13 side of the fluorescent layer.

[0044] The collimator optical system 15 includes a first lens 15a and a
second lens 15b and approximately parallelizes the light output from the
fluorescence generating unit 14. The first lens 15a and the second lens
15b are formed of biconvex lenses. As the first lens 15a and the second
lens 15b, lenses other than the biconvex lenses can be used as long as
the lenses can approximately parallelize the light output from the
fluorescence generating unit 14. Furthermore, the number of the lenses
configuring the collimator optical system 15 may be one, or three or
more.

[0045] The first lens array 16 includes a plurality of small lenses 16a
and divides the light emitted from the light source device LS into a
plurality of partial luminous fluxes. To be more specific, the plurality
of small lenses 16a included in the first lens array 16 is arranged in a
matrix shape that extends in a plurality of rows and a plurality of
columns within a plane perpendicular to an illumination optical axis AX.
The outer shape of the plurality of small lenses 16a included in the
first lens array 16 is approximately similar to the outer shape of the
image forming areas of the liquid crystal optical modulation devices 30R,
30G, and 30B.

[0046] The second lens array 17 has a plurality of small lenses 17a
corresponding to the plurality of small lenses 16a disposed in the first
lens array 16. In other words, the plurality of small lenses 17a included
in the second lens array 17, similarly to the plurality of small lenses
16a included in the first lens array 16, is arranged in a matrix shape
extending in a plurality of rows and a plurality of columns within a
plane perpendicular to the illumination optical axis AX. This second lens
array 17, together with the superposing lens 19, forms images of the
small lenses 16a included in the first lens array 16 near the image
forming areas of the liquid crystal optical modulation devices 30R, 30G,
and 30B.

[0047] The polarization converting device 18 has a polarization separating
layer, a reflection layer, and a retardation film (all of them are not
shown in the figure). The polarization converting device 18 outputs the
partial luminous fluxes divided by the first lens array 16 as linear
polarized light of approximately one type of which the polarization
direction is uniform. Here, the polarization separating layer directly
transmits one linear polarized component out of polarized components
included in the light output from the light source device LS and reflects
the other linear polarized component in a direction perpendicular to the
illumination optical axis AX. In addition, the reflection layer reflects
the other linear polarized component reflected by the polarization
separating layer in a direction parallel to the illumination optical axis
AX. Furthermore, the retardation film converts the other linear polarized
component reflected by the reflection layer into the one linear polarized
component.

[0048] The superposing lens 19 is disposed such that the optical axis
thereof coincides with the optical axis of the illumination device 10.
The superposing lens 19 collects the partial luminous fluxes output from
the polarization converting device 18 and overlaps the partial luminous
fluxes at a position near the image forming areas of the liquid crystal
optical modulation devices 30R, 30G, and 30B. Here, the superposing lens
19 may be configured by one lens or a composite lens acquired by
combining a plurality of lenses. The first lens array 16, the second lens
array 17, and the superposing lens 19 described above configure a lens
integrator optical system that uniformizes the light output from the
light source device LS. Furthermore, instead of the lens integrator
optical system, a rod integrator optical system including an integrator
rod can be used.

[0049] The color separation light guiding optical system 20 includes
dichroic mirrors 21 and 22, reflection mirrors 23 to 25, relay lenses 26
and 27, and light collecting lenses 28R, 28G, and 28B. The color
separation light guiding optical system 20 separates the light emitted
from the illumination device 10 into red light, green light, and blue
light and guides the separated light respectively to the liquid crystal
optical modulation devices 30R, 30G, and 30B. Each of the dichroic
mirrors 21 and 22 is a mirror in which a wavelength selecting
transmission film that reflects light of a predetermined wavelength
region and passes light of other wavelength regions is formed on a
transparent substrate. To be more specific, the dichroic mirror 21
reflects a red light component and transmits a green light component and
a blue light component, and the dichroic mirror 22 reflects the green
light component and transmits the blue light component.

[0050] The reflection mirror 23 is a mirror that reflects the red light
component, and the reflection mirrors 24 and 25 are mirrors that reflect
the blue light component. The relay lens 26 is disposed between the
dichroic mirror 22 and the reflection mirror 24, and the relay lens 27 is
disposed between the reflection mirror 24 and the reflection mirror 25.
Since the length of the optical path of the blue light is longer than
those of the optical paths of other color light, the relay lenses 26 and
27 are disposed so as to prevent a decrease in the use efficiency of
light due to radiation of light or the like. The light collecting lenses
28R, 28G, and 28B collect the red light component reflected by the
reflection mirror 23, the green light component reflected by the dichroic
mirror 22, and the blue light component reflected by the reflection
mirror 25 at the image forming areas of the liquid crystal optical
modulation devices 30R, 30G, and 30B.

[0051] The red light reflected by the dichroic mirror 21 is reflected by
the reflection mirror 23 and is incident to the image forming area of the
liquid crystal optical modulation device 30R for red light through the
light collecting lens 28R. The green light passing through the dichroic
mirror 21 is reflected by the dichroic mirror 22 and is incident to the
image forming area of the liquid crystal optical modulation device 30G
for green light through the light collecting lens 28G. The blue light
passing through the dichroic mirrors 21 and 22 is incident to the image
forming area of the liquid crystal optical modulation device 30B for blue
light sequentially through the relay lens 26, the reflection mirror 24,
the relay lens 27, the reflection mirror 25, and the light collecting
lens 28B.

[0053] Each of the liquid crystal optical modulation devices 30R, 30G, and
30B is a liquid crystal optical modulation device of a transmissive type
that is acquired by tightly sealing a liquid crystal as an electrooptic
material between transparent glass substrates forming one pair and, for
example, includes a polysilicon TFT (Thin Film Transistor) as a switching
element. By modulating the polarization direction of the color light
(linear polarized light) passing through the above-described
incident-side polarizing plates, which are not shown in the figure,
described above in accordance with switching operations of the switching
elements disposed in the liquid crystal optical modulation devices 30R,
30G, and 30B, red image light, green image light, and blue image light
according to an image signal are generated.

[0054] The cross dichroic prism 40 forms a color image by composing the
image light output from the above-described outgoing-side polarizing
plates not shown in the figure. To be more specific, the cross dichroic
prism 40 is an optical member having an approximate cube shape that is
formed by bonding four rectangular prisms. In addition, on the boundary
faces that are acquired by bonding the rectangular prisms and have an
approximately "X" shape, dielectric multi-layer films are formed. The
dielectric multi-layer film formed on one boundary having an approximate
"X" shape reflects red light, and the dielectric multi-layer film formed
on the other boundary face reflects blue light. The red light and the
blue light are bent by the dielectric multi-layer films so as to be
aligned in the traveling direction of the green light, whereby the three
types of color light are composed. The projection optical system 50
projects a color image composed by the cross dichroic prism 40 toward the
screen SCR in an enlarged scale.

[0055] Next, a driving circuit that drives the light source device LS will
be described. FIG. 3 is a block diagram showing the configuration of a
main part of the driving circuit of the light source device included in a
projector. As shown in FIG. 3, the driving circuit 60 of the light source
device LS includes a power source device 61 and a control device 62. The
driving circuit 60 performs driving control of the solid-state light
source array 11 included in the light source device LS by using a power
source PS that is supplied from the outside. The power source PS supplied
from the outside is, for example, a commercial power source of which the
voltage V1 is 100 V.

[0056] Here, for simplification of the description for FIG. 3, the
plurality of solid-state light source elements 11a included in the
solid-state light source array 11 is shown as solid-state light source
elements L1 to L8 in units of eight elements connected in series. In
other words, eight solid-state light source elements 11a that are
arranged in a row C1 shown in FIG. 2 and are connected in series are
shown as the solid-state light source element L1, and eight solid-state
light source elements 11a that are arranged in a row C2 shown in FIG. 2
and are connected in series are shown as the solid-state light source
element L2. Similarly, the solid-state light source elements 11a that are
respectively arranged in rows C3 to C8 shown in FIG. 2 and are connected
in series are respectively shown as the solid-state light source elements
L3 to L8.

[0057] To the cathodes of the solid-state light source elements L1 to L8,
switching elements SW1 to SW8 of which the On state and the Off state are
controlled by the control device 62 are connected. As the switching
elements SW1 to SW8, for example, FETs (Field Effect Transistors) can be
used. Such switching elements SW1 to SW8 are disposed so as to control
the lighting and extinguishing of the solid-state light source elements
L1 to L8. In other words, when the switching elements SW1 to SW8 are in
the On states in accordance with control of the control device 62, the
solid-state light source elements L1 to L8 are in the lighted state. On
the other hand, when the switching elements SW1 to SW8 are in the Off
states, the solid-state light source elements L1 to L8 are in the
extinguished state.

[0058] Since the On states and Off states of the switching elements SW1 to
SW8 can be individually controlled, the lighting and extinguishing
control can be performed for each of the solid-state light source
elements L1 to L8. In addition, amounts of currents supplied to the
solid-state light source elements L1 to L8 when the switching elements
SW1 to SW8 are in the On states can be controlled. By controlling the
amounts of currents supplied to the solid-state light source elements L1
to L8, the light intensity of the blue light emitted from the solid-state
light source array 11 can be changed.

[0059] The power source device 61 generates power (for example, a DC power
of which the voltage V2 is 380 V) used for driving the solid-state light
source array 11 and supplies the generated power to the control device 62
by using power supplied from the power source PS. In this power source
device 61, an instant interruption detecting circuit 61a (instant
interruption detecting device) that detects an instant interruption of
the power source PS, and a detection signal S0 that represents a
detection result of the instant interruption detecting circuit 61a is
output to the control device 62. Although an example is described here in
which the instant interruption detecting circuit 61a is disposed inside
the power source device 61, the instant interruption detecting circuit
61a may be disposed outside the power source device 61.

[0060] In addition, although not shown in FIG. 3, a PFC (Power Factor
Correction) circuit and a capacitor that stores power used for
maintaining the lighting of the solid-state light source array 11 in a
case where an instant interruption occurs are disposed in the power
source device 61. The capacitor that is disposed in the power source
device 61 is set to have capacitance for which the lighting of the
solid-state light source array 11 can be maintained, for example, during
0.5 seconds after the occurrence of the instant interruption, in
consideration of disadvantages of increases in the size and cost of the
power source device 61 according to an increase in the capacitance
thereof.

[0061] The control device 62 includes a voltage detecting circuit 62a that
detects an output voltage (voltage V2) of the power source device 61 and
controls the driving of the solid-state light source array 11 by using
the power supplied from the power source device 61. To be more specific,
the control device 62 controls the On states and Off states of the
switching elements SW1 to SW8 by outputting control signals S1 to S8 to
the switching elements SW1 to SW8 connected to the solid-state light
source elements L1 to L8 of the solid-state light source array 11,
thereby individually controlling the lighting and extinguishing of the
solid-state light source elements L1 to L8. In addition, the control
device 62 controls the amounts of currents supplied to the solid-state
light source elements L1 to L8, thereby controlling the light intensity
of the blue light emitted from the solid-state light source array 11.

[0062] In a case where a detection signal S0 is output from the instant
interruption detecting circuit 61a or in a case where the detection
signal S0 is output and the voltage value detected by the voltage
detecting circuit 62a is less than a threshold voltage Vt set in advance,
the control device 62 performs control for lengthening the time at which
the solid-state light source array 11 can be lighted for reducing the
power consumption of the solid-state light source array 11. As described
above, the capacitance of the capacitor (a capacitor that stores the
power used for maintaining the lighting of the solid-state light source
array 11 in a case where an instant interruption occurs) disposed in the
power source device 61 is decreased in consideration of the disadvantages
accompanied with an increase in the capacitance. Accordingly, even in a
case where a capacitor having low capacitance is disposed in the power
source device 61, in order to lengthen the time for which the solid-state
light source array 11 can be lighted as much as possible, the control
device 62 performs control of decreasing the power consumption of the
solid-state light source array 11.

[0063] To be more specific, during a period until an instant interruption
is recovered after the input of the detection signal S0 representing the
instant interruption of the power source PS, the control device 62
performs control of extinguishing the solid-state light source array 11.
Here, since the solid-state light source array 11 includes a plurality of
solid-state light source elements L1 to L8, the lighting and
extinguishing of the solid-state light source elements L1 to L8 can be
individually controlled by the control device 62. Accordingly, although
various methods may be considered to be used as the method of controlling
the solid-state light source elements L1 to L8 using the control device
62, for example, control methods represented in (1) to (6) shown below
can be used.

(1) Entire Intermittent Extinguishing Control

[0064] This is a control method in which all the solid-state light source
elements L1 to L8 are intermittently extinguished at a specific timing.
To be more specific, in the above-described control method, the control
device 62 outputs the control signals S1 to S8 to the switching elements
SW1 to SW8 at the specific timing so as to allow all the switching
elements SW1 to SW8 to be sequentially in the On state and the Off state
at the specific timing, thereby repeating lighting and extinguishing of
the solid-state light source elements L1 to L8.

(2) Entire Intermittent Extinguishing PWM Control

[0065] This is a method in which a period, during which all the
solid-state light source elements L1 to L8 are intermittently
extinguished, is PWM-controlled. To be more specific, in the
above-described control method, similarly to "(1) Entire Intermittent
Extinguishing PWM Control" described above, although the control device
62 performs control such that all the solid-state light source elements
L1 to L8 are intermittently extinguished at the same timing, the length
of the period during which the solid-state light source elements L1 to L8
are intermittently extinguished is changed (to be longer) in accordance
with an elapse of time after the occurrence of an instant interruption.

(3) Partial Intermittent Extinguishing Control

[0066] This is a method in which only a part of the solid-state light
source elements L1 to L8 is intermittently extinguished at a specific
timing. To be more specific, in the above-described control method, the
control device 62 outputs control signals to only apart of the switching
elements SW1 to SW8 at a specific timing so as to allow the switching
elements, to which the control signals are output, to be sequentially in
the On state and the Off state at a specific timing, thereby repeating
lighting and extinguishing of only a part of the solid-state light source
elements L1 to L8.

(4) Partial Intermittent Extinguishing PWM Control

[0067] This is a method in which a period, during which only a part of the
solid-state light source elements L1 to L8 is intermittently
extinguished, is PWM-controlled. To be more specific, in the
above-described control method, similarly to "(3) Partial Intermittent
Extinguishing Control" described above, although the control device 62
performs control such that only a part of the solid-state light source
elements L1 to L8 is intermittently extinguished at the same timing, the
length of the period during which a part of the solid-state light source
elements L1 to L8 is intermittently extinguished is changed (to be
longer) in accordance with an elapse of time after the occurrence of an
instant interruption.

(5) Entire Extinguishing Control

[0068] This is a method in which all the solid-state light source elements
L1 to L8 are extinguished over the entirety of the instant interruption
period. To be more specific, in the above-described control method, at a
time point when the detection signal S0 is input, the control device 62
outputs the control signals S1 to S8 to the switching elements SW1 to SW8
so as to allow all the switching elements SW1 to SW8 to be in the Off
state, thereby the solid-state light source elements L1 to L8 are
extinguished over the entirety of the instant interruption period.

(6) Partial Extinguishing Control

[0069] This is a method in which only a part of the solid-state light
source elements L1 to L8 is extinguished over the entirety of the instant
interruption period. To be more specific, in the above-described control
method, at a time point when the detection signal S0 is input, the
control device 62 outputs the control signals only to a part of the
switching elements SW1 to SW8 so as to allow the switching elements, to
which the control signals are input, to be in the Off state, and thereby
only apart of the solid-state light source elements L1 to L8 is
extinguished over the entirety of the instant interruption period.

[0070] In addition, the control methods presented in (1) to (4) and (5)
described above may be combined or modified for a more precise control
operation. For example, the control method disclosed in (3) or (4) and
the control method disclosed in (6) may be combined such that, over the
entirety of the instant interruption period, a part of the solid-state
light source elements L1 to L8 is extinguished, and the remaining part is
controlled to be intermittently extinguished. Furthermore, by modifying
the control method disclosed in (6) described above, the solid-state
light source element to be extinguished out of the solid-state light
source elements L1 to L8 may be controlled so as to be sequentially
changed. For example, there is a method in which the solid-state light
source elements L1 to L8 are sequentially extinguished in the mentioned
order in accordance with an elapse of time, and the solid-state light
source elements 11a out of 56 solid-state light source elements 11a
disposed in the solid-state light source array 11 are sequentially
extinguished in units of eight solid-state light source elements. In
addition, the amounts of currents supplied to the solid-state light
source elements L1 to L8 may be controlled in addition to using the
control methods disclosed in (1) to (4) and (5) described above.

[0071] Next, the operation of the projector 1 having the above-described
configuration will be described. FIG. 4 is a flowchart showing the
overview of an operation performed by a projector when an instant
interruption occurs. The flowchart shown in FIG. 4 is a flowchart in a
case where a control process combining the control method disclosed in
(4) and the control method disclosed in (6), which are described above,
is performed by the control device 62. The process shown in this
flowchart is started as the control signals S1 to S8 are output from the
control device 62 disposed in the driving circuit 60, and the switching
elements SW1 to SW8 are in the On state so as to allow the light source
device LS to be in the operating state (the solid-state light source
elements L1 to L8 are lighted).

[0072] First, it is determined whether or not an instant interruption of
the power source PS is detected by the control device 62 disposed in the
driving circuit 60 (Step S11: detection step). To be more specific, it is
determined whether or not a detection signal S0 indicating the detection
of an instant interruption is output from the instant interruption
detecting circuit 61a by the control device 62. In a case where it is
determined that an instant interruption has not been detected (in a case
where the determination result is "No"), the control device 62 maintains
the switching elements SW1 to SW8 in the On state and supplies a constant
current to the solid-state light source elements L1 to L8, thereby
allowing the solid-state light source elements L1 to L8 to continue to be
lighted (Step S12).

[0073] On the other hand, in a case where an instant interruption is
detected (in a case where the determination result of Step S11 is "Yes"),
the control device 62 determines whether or not each of the solid-state
light source elements L1 to L8 is a solid-state light source element to
be extinguished (Step S13). Here, for example, assuming that the
solid-state light source elements L1 to L3 are set in advance as
solid-state light source elements to be extinguished, the control device
62 outputs control signals S1 to S3 so as to allow the switching elements
SW1 to SW3 connected to the solid-state light source elements L1 to L3 to
be in the Off state, thereby extinguishing the solid-state light source
elements L1 to L3 (Step S14: control step).

[0074] Next, the control device 62 determines whether each of the
solid-state light source elements L1 to L8 is a solid-state light source
element to be intermittently extinguished (Step S15). Here, for example,
assuming that the solid-state light source elements L4 to L6 are set in
advance as the solid-state light source elements to be intermittently
extinguished, the control device 62 performs PWM control for the
switching elements SW4 to SW6 connected to the solid-state light source
elements L4 to L6 so as to intermittently extinguish the solid-state
light source elements L4 to L6 (Step S16: Control Step).

[0075] By the above-described control process, the "partial extinguishing
control" is performed for three solid-state light source elements L1 to
L3 out of the solid-state light source elements L1 to L8, and the
"partial intermittent extinguishing PWM control" is performed for three
solid-state light source elements L4 to L6. In addition, a constant
current is supplied to the remaining two solid-state light source
elements L7 and L8 from the control device 62, so that the two
solid-state light source elements L7 and L8 continue to be lighted. As
above, when an instant interruption occurs, the "partial extinguishing
control", the "partial intermittent extinguishing PWM control", or the
like are performed for the solid-state light source elements L1 to L8.
Therefore, the power consumption of the solid-state light source array 11
is decreased, and the period during which the solid-state light source
array 11 can be lighted can be longer than that of a general case.

[0076] In a case where any of the control processes disclosed in (1) to
(4) described above is performed by the control device 62, the
determination result of Step S13 is "No", and the determination result of
Step S15 is "Yes". Accordingly, the intermittent extinguishing control
process or the intermittent extinguishing PWM control is performed for
all or a part of the solid-state light source elements L1 to L8 in Step
S16. On the other hand, in a case where any of the control processes
disclosed in (5) and (6) described above is performed by the control
device 62, the determination result of Step S13 is "Yes", and the
determination result of Step S15 is "No". Therefore, the extinguishing
control process is performed for all or a part of the solid-state light
source elements L1 to L8 in Step S14.

[0077] Next, several examples of a change (intensity change in blue light)
in the optical output of the light source device LS at the time of
occurrence of an instant interruption of the power source PS will be
described. FIGS. 5 to 7 are diagrams showing examples of the change in
the optical output of the light source device included in a projector
when an instant interruption occurs. FIG. 5 is a diagram showing a change
in the optical output of the light source device LS when the "entire
intermittent extinguishing control" disclosed in (1) described above is
performed. FIG. 6 is a diagram showing a change in the optical output of
the light source device LS when the "entire intermittent extinguishing
PWM control" disclosed in (2) described above is performed. FIG. 7 is a
diagram showing a change in the optical output of the light source device
LS when a control process combining the "entire intermittent
extinguishing PWM control" disclosed in (2) described above and a control
process of the amounts of currents supplied to the solid-state light
source elements L1 to L8 is performed.

[0078] First, the example shown in FIG. 5 will be described. In this
example, the "entire intermittent extinguishing control" is performed by
using the detection result of the voltage detecting circuit 62a, in
addition to the detection result of the instant interruption detecting
circuit 61a shown in FIG. 3. As shown in FIG. 5, when an instant
interruption of the power source PS occurs at time t1, the detection
signal S0 output from the instant interruption detecting circuit 61a
changes from the H (high) level to the L (low) level. When the detection
signal S0 changes to the L level, it is determined whether the detection
voltage of the voltage detecting circuit 62a (that is, the output voltage
V2 of the power source device 61) is lower than the threshold voltage Vt
set in advance by the control device 62.

[0079] In a case where the detection voltage of the voltage detecting
circuit 62a is not lower than the threshold voltage Vt, the solid-state
light source elements L1 to L8 continue to be lighted. Accordingly, the
power accumulated in a capacitor, which is not shown in the figure,
disposed in the power source device 61 is slowly consumed, and the output
voltage V2 of the power source device 61 is slowly lowered. Now, as shown
in FIG. 5, it is assumed that the detection voltage of the voltage
detecting circuit 62a at time t2 is lower than the threshold voltage Vt.
Then, the control device 62 performs the "entire intermittent
extinguishing control", and accordingly, all the solid-state light source
elements L1 to L8 are intermittently extinguished at a specific timing.

[0080] By intermittently extinguishing the solid-state power source
elements L1 to L8, the power consumption is reduced, and, as denoted by a
curve to which a reference sign Q11 is assigned, the rate of decrease in
the output voltage V2 is gentle. In FIG. 5, a curve to which a reference
sign Q12 is assigned is a curve that represents a change in the output
voltage V2 in a case where the solid-state light source elements L1 to L8
continue to be lighted also after time t2. As above, by performing the
"entire intermittent extinguishing control" by using the control device
62, the period (a period until the output voltage V2 becomes zero) during
which the solid-state light source array 11 can be lighted can be
lengthened.

[0081] Next, the example shown in FIG. 6 will be described. As shown in
FIG. 6, when an instant interruption of the power source PS occurs at
time t1, the detection signal S0 output from the instant interruption
detecting circuit 61a changes from the H level to the L level. When the
detection signal S0 changes to the L level, the control device 62
performs the "entire period extinguishing PWM control" such that the
length of the period during which all the solid-state light source
elements L1 to L8 are intermittently extinguished is gradually
lengthened.

[0082] By intermittently extinguishing the solid-state power source
elements L1 to L8, the power consumption is reduced, and, as denoted by a
curve to which a reference sign Q21 is assigned, the rate of decrease in
the output voltage V2 is gentle. In FIG. 6, a curve to which a reference
sign Q22 is assigned is a curve that represents a change in the output
voltage V2 in a case where the solid-state light source elements L1 to L8
continue to be lighted also after time t1. As above, by performing the
"entire intermittent extinguishing PWM control" by using the control
device 62, the period (a period until the output voltage V2 becomes zero)
during which the solid-state light source array 11 can be lighted can be
lengthened.

[0083] Next, the example shown in FIG. 7 will be described. In the example
shown in FIG. 7, similarly to the example shown in FIG. 6, after time t1
when an instant interruption of the power source PS occurs, the control
device 62 performs the "entire period extinguishing PWM control". In
addition, in the example shown in FIG. 7, the amount of currents supplied
to the solid-state light source elements L1 to L8 during the period in
which the solid-state light source elements L1 to L8 are lighted is
decreased. Accordingly, after time t1, the optical output of the light
source device LS is lowered by about a half.

[0084] By decreasing the amount of currents in addition to intermittently
extinguishing the solid-state power source elements L1 to L8, the power
consumption is reduced, and, as denoted by a curve to which a reference
sign Q31 is assigned, the rate of decrease in the output voltage V2
becomes gentler. As above, by performing the "entire intermittent
extinguishing PWM control" and the control of decreasing the amount of
currents by using the control device 62, the period (a period until the
output voltage V2 becomes zero) during which the solid-state light source
array 11 can be lighted can be lengthened.

[0085] As above, according to this embodiment, in a case where an instant
interruption of the power source PS occurs, the control device 62
performs control of extinguishing the solid-state light source array 11
during at least a part of an instant interruption period until recovery
from the occurrence of the instant interruption. Therefore, according to
this embodiment, the period during which the solid-state light source
array 11 can be lighted can be configured to be longer than that of a
general case.

[0086] Here, by extinguishing the solid-state light source array 11 over
the entirety of the instant interruption period, the power consumption of
the solid-state light source array 11 can be almost zero. The solid-state
light source array 11 can be relighted even after being extinguished.
Accordingly, by performing control of lighting the solid-state light
source array 11 at an arbitrary timing by using the control device 62,
the solid-state light source array 11 can be instantly relighted by the
power accumulated in the capacitor of the power source device 61.

[0087] As above, although the projection-type display device and the
method of controlling thereof according to one embodiment of the
invention have been described, the invention is not limited to the
above-described embodiments, and a change can be freely made within the
scope of the invention. For example, modified examples described below
can be applied.

[0088] In the above-described embodiment, a configuration has been
described in which the light source device LS emitting blue light as
excitation light and the fluorescence generating unit 14 converting a
part of the blue light emitted from the light source device LS into red
light and green light are included. However, the invention is not limited
thereto. For example, a configuration may be employed in which a light
source device emitting violet light or ultraviolet light as excitation
light and a fluorescent layer generating color light including red light,
green light, and blue light from the violet light or the ultraviolet
light are included. In addition, in the above-described embodiment, an
example has been described in which the illumination device 10 is
configured so as to emit white light as a whole. However, the invention
is not limited thereto. The illumination device 10 may be configured so
as to emit light other than the white light.

[0089] In the above-described embodiment, a case has been described as an
example in which the solid-state light source elements 11a (the
solid-state light source elements L1 to L8) arranged in the solid-state
light source array 11 are semiconductor laser devices. However, the
invention is not limited thereto. For example, the invention can be
applied to a solid-state light source array in which solid-state light
source elements are light emitting diodes. In addition, in the
above-described embodiment, an example has been described in which a
plurality of solid-state light source devices is included. However, the
invention can be applied to a case where only one solid-state light
source element is included.

[0090] In the above-described embodiment, an example has been described in
which semiconductor laser devices emitting blue light of which the peak
of the emission intensity is about 460 nm are used as the solid-state
light source elements 11a (the solid-state light source elements L1 to
L8). However, the invention is not limited thereto. For example,
semiconductor laser devices emitting blue light of which the peak of the
emission intensity is in the range of 440 to 450 nm may be used as the
solid-state light source elements 11a (the solid-state light source
elements L1 to L8). By using such semiconductor laser devices, the
efficiency of generating fluorescence from blue light can be improved.

[0091] In the above-described embodiment, although a transmissive-type
projector has been described as an example of the projection-type display
device, the invention is not limited thereto. For example, the invention
may be applied to a reflective-type projector. Here, "transmissive-type"
means that the optical modulation device transmits light as in a
transmissive-type liquid crystal display device or the like, and
"reflective-type" means that the optical modulation device reflects light
as in a reflective-type liquid crystal display device or the like. Even
in a case where an embodiment of the invention is applied to a
reflective-type projector, advantages similar to those of the
transmissive-type projector can be acquired.

[0092] In the above-described embodiments, although an example has been
described in which the liquid crystal optical modulation device is used
as the optical modulation device, the invention is not limited thereto.
As the optical modulation device, generally, a device that modulates
incident light in accordance with an image signal may be used. Thus, a
light valve, a micro-mirror type optical modulation device, or the like
can be used. As the micro-mirror type optical modulation device, for
example, a DMD (Digital Micro-Mirror Device) (a trademark of Texas
Instruments, Inc.) can be used.

[0093] In the above-described embodiments, although a projector using
three liquid crystal optical modulation devices has been described as an
example, the invention is not limited thereto. Thus, the invention can be
applied to a projector that uses one, two, or four or more liquid crystal
optical modulation devices.

[0094] The invention can be applied to a front projection-type projector
that projects a projection image from the observation side or a rear
projection-type projector that projects a projection image from a side
opposite to the observation side.